Electrical control apparatus



i 1941- H. E. ASHWORTH 2,250,214

ELECTRICAL CONTROL APPARATUS Filed Dec. 3Q. 1939 H E INVENTORZ h C(II BY H15 ATTO R N EY Patented July 22, 1941 UNITED STATES PATENT OFFICE ELECTRICAL CONTROL APPARATUS of Pennsylvania Application December 30, 1939, Serial No. 311,955

6 Claims.

My invention relates to electrical control apparatus, and particularly to apparatus for effecting one function when a control circuit is energized by current of one relative polarity and another function when the control circuit is energized by current of the other relative polarity.

Heretofore, control apparatus of the type described has in many instances, comprised a polar neutral relay having polarized contacts which assume one position or another in accordance with the polarity of the current supplied to the control circuit and neutral contacts which close whenever the relay is supplied with current of either polarity. With this type of relay it sometimes happens that the polar armature will fail to reverse for some reason when current of reverse polarity is supplied to the relay winding but the neutral contacts will still close and will thus cause the controlled apparatus to function improperly.

One object of my present invention is to provide means for insuring that the controlled apparatus will not function unless the polar contacts of the polar relay assume a position corresponding to the polarity of the current supplied to the control circuit, and that if they do assume the opposite position the result will be the same as if the control circuit had not been energized.

According to my invention I accomplish the desired result by employing in addition to the polar relay an auxiliary relay the armature of which will pick up when the relay winding is supplied with current of one polarity but will move to and remain in its deenergized position when the relay winding is supplied with current of the other polarity. Both relays are supplied with operating current from the same polarized control circuit, the polar relay being connected directly with the circuit and the auxiliary relay being connected with the circuit over pole changing contacts of the polar relay. The parts are so arranged and so proportioned that when the polarity of the control circuit is reversed, the resultant reversal of the polar contacts of the polar relay will cause the auxiliary relay to always be supplied with current of the proper polarity to operate its armature, whereby if the polar relay should fail to reverse its polar contacts for any reason in response to a change in the polarity of the current supplied to the control circuit, the auxiliary relay will become deenergized to provide an indication that the polar relay has failed to operate as intended.

Such an arrangement is particularly useful in certain forms of railway signaling systems wherein the signal indications depend upon the position of the polar armature of the polar relay, and it is desired to insure that an indication will not be given unless the polar armature reverses in the proper manner, the necessary check on the operation of the polar relay being provided by including in the signal circuits a front contact of the auxiliary relay. With this arrangement the signal circuits will become closed as long as the polar relay operates as intended but if it fails to so operate the auxiliary relay will fail to close its front contacts and will then prevent a dangerous indication from being given.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

The present application is a continuation in part of my copending application for Letters Patent of the United States, Serial No. 194,160, filed on March 5, 1938, for Electrical relays.

I shall describe one form of electrical control apparatus embodying my invention, and shall I then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating one form of apparatus embodying my invention.

Referring to the drawing, the reference character P designates a polar relay, the winding of which is arranged to be supplied with current directly from a polarized control circuit here shown for convenience as comprising a pair of wires or conductors i0 and II connected with a battery B over a pole changer PC. The polarized control circuit may for example comprise a line circuit in which event the conductors l0 and I I would be line wires, or it may comprise a track circuit in which event the wires l0 and II would comprise the track rails of a section of railway track. Furthermore, the pole changer PC may be operated manually or may comprise contacts of another relay, signal mechanism or the like. The polar relay is provided with polar contacts I2, I 3 and I4, and it will be obvious that under normal conditions these contacts will occupy their normal positions in which they are shown in the drawing or their reverse positions according as the pole changer P occupies the position shown or its opposite position.

The use of a polar relay controlled by means of a polarized control circuit in the manner thus far described for selectively effecting control functions in accordance with the polarity of the current supplied to the control circuit is well known in railway signaling and other control applications. When a polar relay is thus used, however, it sometimes happens that the relay armature fails to respond to a reversal of the current supplied to the control circuit, and as a result the apparatus controlled by the polar relay is caused to function improperly. This failure of the polar relay to respond to a reversal of the current supplied to its winding may be caused in a variety of ways. For example, the polar contacts may stick in their last operated positions as a result of frost on the contacts or they may burn fast due to lightning discharges or arcing caused by improper adjustment, or when the relay is of the type having its polar field supplied by a permanent magnet, the permanent magnet may become weakened due to age or to overenergization of the relay or it may even have its polarity reversed as a result of lightning discharges.

In many applications it is imperative to insure that the controlled apparatus will not function unless the polar contacts of the relay assume a position corresponding to the polarity of the current supplied to the control circuit, and that if they do assume the opposite position, the result so far as the controlled apparatus is concerned will be the same as if the control circuit had not been energized. To this end, I employ in connection with the polar relay for effecting the desired controlled functions an auxiliary or checking relay R the energizing winding of which is connected with the conductors Ill and H of the control circuit over the contacts [2 and I3 of the polar relay P. The relay R is of a type having an armature which will pick up when the relay winding is supplied with current of one relative polarity, but will remain in its deenergized position when the relay winding is supplied with current of the other relative polarity, and the contacts l2 and 13 are arranged as pole changing contacts in such manner that when the current in the control circuit is reversed if the polar contacts 22 and I3 reverse in the proper manner they will cause the auxiliary relay to always be supplied with current of the proper polarity to pick up its armature, but that, if these polar contacts fail to reverse then the auxiliary relay will be suppled with current of the polarity which causes its armature to move to and remain in its deenergized position. One form of relay which will operate in the manner described is disclosed and claimed in my prior copending application,

' Serial No. 194,160, of which application the present application is a continuation, while another form of relay which will operate in this manner is described and claimed in Letters Patent of the United States No. 2,057,605 granted to Herman G. Blosser, on October 13, 1936, for Electrical relays.

As has been pointed out hereinbefore, apparatus embodying my invention is particularly suitable for, although in no way limited to, use in certain forms of signaling systems wherein some of the signal indications depend upon the position of the polar armature of the polar relay and it is desired to insure that these indications will not be given unless the polar armature of the polar relay occupies a position corresponding to the polarity of the current supplied to the control circuit, and I have accordingly illustrated in the drawing one arrangement for controlling a signal S by means of the two relays P and R in a manner to accomplish the desired result.

Referring again to the drawing, the signal S as here illustrated is of the color light type and comprises a green lamp G, a yellow lamp Y and a red lamp R, which lamps when illuminated indicate proceed, caution and stop, respectively. The green lamp G is provided with a circuit which passes from terminal X of a suitable source of current not shown in the drawing through front contact l5|5a of relay R, normal polar contact [4 of relay P and the filament of lamp G to terminal 0 of the source. It will be apparent therefore that this lamp will become lighted when and only when the polar armature of relay P occupies its normal position and the armature of relay R is picked up.

The yellow lamp Y of signal S is provided with a circuit which passes from terminal X through front contact l5l5a of relay R, reverse polar contact M of relay P and the filament of lamp Y to terminal 0. It will be obvious that this lamp will be lighted only when the polar contacts of relay P occupy their reverse position and the armature of relay R is picked up.

The red lamp R of signal S is provided with a circuit which passes from terminal X through back contact l5|E-b of relay R and the filament of lamp R to terminal 0. It follows that lamp R will be lighted when and only when the armature of relay R occupies its deenergized position.

With the signal controlled in this manner it will be seen that under normal conditions the green lamp G, the yellow lamp Y or the red lamp R will be lighted according as the control circuit is supplied with current of normal or reverse polarity or is deenergized.

I will now assume that the pole changer PC is reversed to reverse the polarity of the current supplied to the control circuit but that the polar relay P fails to reverse its polar armature for some reason so that the polar contacts remain in the position shown. Under these conditions, relay R will be supplied with current of the polarity which will cause its armature to move to its deenergized position and stay there, and as a result, instead of the yellow light Y becoming lighted as would normally have been the case, the red lamp R will become lighted, thereby causing the signal S to display the same indication it would have displayed had the control circuit been deenergized.

A similar result would be obtained if the control circuit had been supplied with current of normal polarity when the polar armature of relay P occupied its reverse position and the polar armature had remained in this position.

It will be seen therefore that apparatus embodying my invention provides a means for obtaining additional safety with standard relays.

Although I have herein shown and described only one form of control apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a polarized control circuit, a polar relay having its winding connected with said circuit and having polar contacts responsive to the polarity of the current supplied to said circuit, and an auxiliary relay which will respond to current of one polarity only connected with said control circuit over pole changing contacts of said polar relay in such manner that said auxiliary relay will be supplied with current of the polarity to which it will respond if and only if the polar contacts of said polar relay occupy positions corresponding to the polarity of the current supplied to said control circuit.

2. In combination, a polarized control circuit, a polar relay having its winding connected with said circuit and having polar contacts responsive to the polarity of the current supplied to said circuit, an auxiliary relay having an armature which will pick up when the relay winding is supplied with current of one relative polarity and will remain in its deenergized position when the relay winding is supplied with current of the other relative polarity, said auxiliary relay having its winding connected with said control circuit over pole changing contacts of said polar relay in such manner that it will be supplied with current of the polarity which will cause its armature to pick up when and only when the polar contacts of said polar relay occupy positions in agreement with the polarity of the current supplied to said control circuit, and means selectively responsive to the positions of the polar contacts of said polar relay when the armature of said auxiliary relay is picked up.

3. In combination, a pair of conductors which are reversibly connected with a source of current, a polar relay receiving current from said source over said wires, 2, second relay which will pick up its armature on current of one polarity only, and means including pole changing con tacts on said polar relay for reversibly connecting the energizing winding of said second relay with said two conductors respectively in such manner that said second relay will always be supplied with current of said one polarity regardless of the polarity of the current supplied to said conductors provided the polar contacts of said polar relay assume positions in agreement with the polarity of the current supplied to said conductors.

4. In combination, a control circuit comprising a pair of conductors, means for at times impressing given polarity potential upon said conductors and for at other times impressing opposite polarity potential thereupon, a polar relay connected across said conductors and responding distinctively to each polarity of the said potential which appears therebetween, an auxiliary relay which picks up when and only when given direction current is passed through the winding thereof, contacts of said polar relay which connect said auxiliary relay winding directly across said circuit conductors when in their given polarity position and reversely across those conductors when in their opposite polarity position whereby control circuit potential of either of said two polarities passes given direction current through said winding when and only when said polar relay contacts are in positional agreement with the polarity of that potential, and apparatus controlled by a contact of said auxiliary relay aided by a contact of said polar relay.

5. In combination, a control circuit comprising a pair of conductors, means for energizing said conductors with given polarity potential at times and with opposite polarity potential at other times, a polar relay having a winding connected with said conductors and being provided with contacts which respond distinctively to each polarity of the said control circuit potential which said winding receives, an auxiliary relay which responds when and only when given direction current is passed through the winding thereof and which stays released when opposite direction current or no current at all is passed through said winding, means for causing said polar relay contacts to connect said auxiliary relay winding directly across said circuit conductors when in their given polarity position and reversely across those conductors when in their opposite polarity position whereby control circuit potential of either polarity can pass current through said winding in said given direction when and only when accompanied by a positional correspondence of said polar relay contacts, and apparatus controlled by a contact of said auxiliary relay aided by a contact of said polar relay.

6. In combination, a control circuit comprising a pair of conductors, means at one end of said circuit for at times supplying given polarity potential to said conductor and for at other times supplying opposite polarity potential thereto, a polar relay at the other end of said circuit connected with said conductors and responding distinctively to each polarity of the said potential which is received therefrom, an auxiliary relay also at said other circuit end which picks up when and only when given direction current is passed through the winding thereof, contacts of said polar relay which connect the winding of said auxiliary relay directly across said circuit conductors when in their given polarity position and reversely across those conductors when in their opposite polarity position whereby control circuit potential of either polarity can pass current through said winding in said given direction when and only when accompanied by a positional correspondence of said polar relay contacts, and apparatus controlled by a contact of said auxiliary relay aided by a contact of said polar relay.

HARRY E ASHWORTH. 

